hydrodynamic Rock Buggy - datsun Engine - Photo 12

Powering the buggy is a propane-fired 2.8-liter I-6 from a '78 Datsun 280Z. The engine is rated at 170 horsepower and 150 lb-ft of torque, but Friesen calculates that at the lower rpm he's using, it's making about 125 horsepower and 125 lb-ft of torque. Friesen says the Delco 150-amp alternator is a Freightliner big-rig application unit that is rated at 10,000 rpm. He says the pulley size is calculated to run at about 9,000 rpm when the engine is at 4,000 rpm. This allows for maximum cooling and output so the alternator can put out a full continuous 150 amps without getting hot and burning up. The buggy uses a pair of Orbital batteries. Friesen designed the battery and charging system to be able to handle the task of recovery (i.e., extended winching) in case of hydraulic failure.